DE102015219735A1 - Device for detecting an object - Google Patents

Abstract

An apparatus (100) for detecting an object, comprising: - a magnetic field sensor (10); - a computing device (20); - a radio-based transmission device (30); - wherein by means of the magnetic field sensor (10) and the computing device (20) a determination of a magnetic field vector in a measuring range of the magnetic field sensor (10) is feasible, wherein a change of the determined magnetic field vector relative to a defined initial value can be determined, wherein data of the detected magnetic field vector by means of the transmission device (30) is transferable; and - an electrical energy store (40) by means of which the magnetic field sensor (10), the computing device (20) and the radio-based transmission device (30) can be supplied with electrical energy.

Description

The invention relates to a device for detecting an object. The invention further relates to a method for detecting an object.

State of the art

The determination of the occupancy rate of multi-storey car parks and paid car parks is of great importance for their operation and traffic regulation in cities. Therefore, sensors are used to monitor parking spaces, which transmit the state of the parking lot to a control point. The detection of the condition is usually either via magnetic field sensors, cameras or by emitting sensors such as ultrasonic or radar sensors, or a combination of these sensors.

Disclosure of the invention

It is an object of the present invention to provide an improved apparatus for detecting an object.

• – einen Magnetfeldsensor;
• – eine Recheneinrichtung;
• – eine funkbasierte Übertragungseinrichtung;
• – wobei mittels des Magnetfeldsensors und der Recheneinrichtung eine Ermittlung eines Magnetfeldvektors in einem Messbereich des Magnetfeldsensors durchführbar ist, wobei eine Änderung des ermittelten Magnetfeldvektors gegenüber einem definierten Initialwert ermittelbar ist, wobei Daten des erfassten Magnetfeldvektors mittels der Übertragungseinrichtung übertragbar sind; und
• – einen elektrischen Energiespeicher mittels dessen der Magnetfeldsensor, die Recheneinrichtung und die funkbasierte Übertragungseinrichtung mit elektrischer Energie versorgbar sind.

According to a first aspect, the object is achieved with a device for detecting an object, comprising:

• A magnetic field sensor;
• A computing device;
• A radio-based transmission device;
• - wherein by means of the magnetic field sensor and the computing device, a determination of a magnetic field vector in a measuring range of the magnetic field sensor is feasible, wherein a change of the determined magnetic field vector relative to a defined initial value can be determined, wherein data of the detected magnetic field vector can be transmitted by the transmission device; and
• - An electrical energy storage means of which the magnetic field sensor, the computing device and the radio-based transmission device are supplied with electrical energy.

• – Ermitteln eines Magnetfeldvektors in einem Messbereich des Magnetfeldsensors;
• – Vergleichen des erfassten Magnetfeldvektors mit einem in einer Initialisierungsphase ermittelten Magnetfeldvektor, und
• – Signalisieren, falls eine Änderung wenigstens eines Parameters des Magnetfeldvektors detektiert wurde.

According to a second aspect, the object is achieved with a method for detecting an object, comprising the steps:

• - Determining a magnetic field vector in a measuring range of the magnetic field sensor;
• Comparing the detected magnetic field vector with a magnetic field vector determined in an initialization phase, and
• Signaling, if a change of at least one parameter of the magnetic field vector has been detected.

In this way, an object in the vicinity of the magnetic field sensor can be detected, wherein further data on the object can be obtained. Due to the evaluation of the geomagnetic field by magnitude and direction and minor changes in the environment of the magnetic field sensor can be seen, so that statements about external conditions of the detected object can be made. By means of the radio-based transmission device, this information can be transmitted efficiently and promptly to a remote system for further processing or evaluation.

Advantageously, the device can be used in environments in which no line-connected power network is available for power supply purposes. As a result, an expense in an installation of the device can be advantageously kept low.

Advantageous developments of the device are the subject of dependent claims.

An advantageous development of the device is characterized in that a length and an angle of the magnetic field vector can be determined. As a result, the geomagnetic field is detected in spatial aspects, and it can thereby efficiently determine an effect of an object on the earth's magnetic field. In this way, statements about properties and parameters of the object can be made.

A further advantageous development of the device is characterized in that the initial value of the magnetic field vector in the measuring range of the magnetic field sensor can be detected without an object. As a result, comparisons of detected magnetic field vectors with the initial value can be carried out, as a result of which changes in the earth's magnetic field are easily recognizable.

A further advantageous development of the device is characterized in that a geomagnetic field in the x-, y-, and z-direction can be determined in the measuring range of the magnetic field sensor. In this way, changes in the Earth's magnetic field can be detected mathematically well defined.

A further advantageous development of the device provides that by means of at least one threshold value for an amount and / or an angle of the magnetic field vector it is possible to determine whether an object is located in the measuring range of the magnetic field vector. A recognition or detection accuracy of the device can be defined by defined thresholds.

A further advantageous development of the device is characterized in that it can be determined whether an angle of the Magnetic field vector has changed or whether a length of the magnetic field vector has changed or whether the angle and the length of the magnetic field vector have changed, each defined tolerance thresholds for detecting a change are taken into account. In this way, predefined criteria are implemented by means of which the presence of an object can be determined in a simple and reliable manner.

A further advantageous development device provides that, in particular, a vehicle can be detected on a parking area. This provides a useful use case for the device for which it can be efficiently and effectively determined whether the parking area is still empty or already occupied.

A free parking area refers in particular to a parking area on which no vehicle is located. An occupied parking area refers in particular to a parking area on which a vehicle is located.

A further advantageous development of the device is characterized in that it has a second active sensor device, wherein by means of the second sensor device a substantially error-free detection of an object in the measuring range of the magnetic field sensor can be carried out. In this way, for example, by means of the active sensor device in the form of a radar sensor or an ultrasonic sensor, a detection in the measuring range of the magnetic field sensor can be performed with high detection quality. As a result, for example, a reliable initial value for the magnetic field vector can be determined.

Disclosed device features result analogously from corresponding disclosed method features and vice versa. This means, in particular, that features, technical advantages and embodiments relating to the device result analogously from corresponding embodiments, features and advantages of the method and vice versa. In other words, this means, in particular, that technical functionalities of the method result from the device and vice versa.

The invention will be described below with further features and advantages with reference to two figures in detail. In this case, all disclosed features, regardless of their relationship in the claims and regardless of their representation in the description and in the figures form the subject of the present invention.

In the figures shows:

1 a schematic flow diagram of an embodiment of the method according to the invention; and

2 a schematic block diagram of an embodiment of the device according to the invention.

Description of embodiments

1 shows a schematic flow diagram of an embodiment of the method.

In one step 200 is by means of a device 100 for detecting an object in a measuring range of a magnetic field sensor 10 the device 100 a so-called "magnetic fingerprint" of a geomagnetic field in the form of a magnetic field vector determined. The measuring range of the magnetic field may be, for example, a parking area on which vehicles, in particular motor vehicles, are usually parked.

In one step 201 a new measured value is available because of a change in the measuring range of the magnetic field sensor 10 occurred, for example, because a vehicle was parked or removed on the parking area.

In one step 202 is by means of the device 100 recorded a new measured value of the earth's magnetic field in the form of a new magnetic field vector.

In one step 203 an absolute value of the newly detected magnetic field vector is determined, wherein the absolute value represents a strength of the measured earth magnetic field.

In one step 204 will have a cosine similarity between those in the steps 200 and 202 detected magnetic fingerprints, whereby an angle α between the two magnetic field vectors is determined. For this purpose the following mathematical formula is used:

a

Initialwert des Magnetfeldvektors

b

neuer Magnetfeldvektor

α

Winkel zwischen den Magnetfeldvektoren a und b

cosα = a × b / || a || × || b || with the parameters:

a

Initial value of the magnetic field vector

b

new magnetic field vector

α

Angle between the magnetic field vectors a and b

In one step 205 it is checked whether the angle α is smaller than a first threshold value SW1 and a difference of the magnitude values of the magnetic field vectors a , b is greater than a second threshold value SW2. If this is the case, in one step 206 an object, such as a vehicle detected on a parking area.

If in step 205 the angle α is not smaller than the first threshold value SW1, and a difference of the magnitude values of the magnetic field vectors a , b is not larger than the second threshold value SW2 becomes in one step 207 checked whether the angle α is smaller than the first threshold value SW1. If this is the case, in one step 208 detects an object, for example in the form of a vehicle on a parking area.

If in step 207 the angle α is greater than the first threshold SW1, becomes in one step 209 checked whether a difference of the magnitude values of the magnetic field vectors is greater than the second threshold value SW2. If this is the case, in one step 210 detects an object, for example in the form of a vehicle on a parking area. If this is not the case, in one step 211 no object detected. After processing the steps 206 . 208 . 210 and 211 the process branches to a program end that in an endless mode to step 200 can branch.

It goes without saying that during the test steps 205 . 207 and 209 in which values are checked, defined and definable tolerance thresholds are taken into account.

In an initialization phase of the method, for example, in each step 200 is performed, the initial value of the geomagnetic field vector in a measuring range of the device 100 detected, wherein no detectable object is arranged in the measuring range.

2 shows a schematic block diagram of an embodiment of the device 100 for detecting an object. The device 100 includes a magnetic field sensor 10 , which is formed as a passive magnetic field sensor and periodically measures the earth's magnetic field acting on it. An operation of the magnetic field sensor 10 can be based on the Hall effect, since no signal is emitted, but only in a passive way, a geomagnetic field is measured. Such magnetic field sensors 10 are known.

For example, it may be provided to provide a defined cycle for performing the periodic measurements. For this purpose, a computing device 20 provided, preferably in the form of a microcontroller, which executes a software that covers the entire device 100 controls and calculates the magnetic field vector.

Further, in the device 100 a radio-based transmission device 30 (Eg, based on GSM, EDGE, UMTS, WLAN, LTE, etc.) provided over the data of the magnetic field vector or a detected object to a higher-level unit (for example in the form of a server device, not shown,) are transmitted wirelessly. Preferably, a communication between the radio-based transmission device 30 and the parent unit of choice can be encrypted or unencrypted. An electrical energy storage device 40 , For example in the form of a battery or a rechargeable battery is provided to the elements 10 . 20 and 30 the device 100 to supply with electrical energy.

The on the computing device 20 running software provides that the magnetic field sensor 10 periodically (eg, approximately every five to twenty seconds, preferably approximately every ten seconds) is activated to thereby change the earth's magnetic field in the measuring range (for example, a parking area, a parking bay of a road, a parking garage, etc.) of the magnetic field sensor 10 determine and thus recognize whether a vehicle is on the parking area or not.

It will be by means of the magnetic field sensor 10 thus periodically recorded new measured values of the earth's magnetic field in order to determine the said state changes. The determination of the earth's magnetic field is preferably carried out in three spatial coordinates or components, an x-component, a y-component and a z-component, which together have a spatial effect of the earth's magnetic field on the magnetic field sensor 10 represent. The measurement is then compared with a previously formed magnetic fingerprint of the empty parking lot (initial value of the magnetic field vector). This is done by representing the three components of the magnetic fingerprints as a spatial vector and calculating a cosine similarity between the vectors according to the above mathematical relationship.

In this way, a reliable detection of a state of the parking space (busy or unoccupied) can be performed, as an effect of a spatial change of the magnetic field on the magnetic field sensor 10 is detected. This may be particularly advantageous for smaller or higher vehicles, as these usually lower impact on the means of the magnetic field sensor 10 have measured earth magnetic field.

It is advantageously supported in this way that conclusions can be made on parked vehicle types, since each vehicle can have different effects on the measured magnetic field. Furthermore, it is also possible to determine how geometrically oriented the vehicle is arranged on the surface. As a result, data can be collected that identifies different vehicle types. From these data, the types of vehicles can be treated specifically in different ways, for example regarding a charging of parking fees.

As a result, it is also possible to record a statistical evaluation of a use of the parking area over a defined period of time and in this way to enable efficient parking space management.

It is thus advantageously possible with the proposed method to detect different objects, since both the deflection of the magnetic field and the amount of the action of the magnetic field are taken into account. As a result, even smaller objects with a weak effect on the earth's magnetic field can advantageously be detected.

In a preferred embodiment of the device 100 a second active sensor device (not shown) may be provided, for example in the form of a radar sensor, an ultrasonic sensor, infrared sensor, etc.), with which a substantially error-free detection in the vicinity of the device 100 can be carried out. It is advantageous in this case due to the periodic activations of the passive magnetic field sensor 10 and thereby achieved reliable measurement of the earth's magnetic field rarely required to make measurements by means of the additional second active sensor device.

As a result, can advantageously be a power-saving operation of the device 100 be provided because of the electrical energy storage 40 is spared. As a result, a maintenance effort can be reduced, or even completely waived, because the operating life of the energy storage 40 is substantially equal to a product life.

In summary, the present invention describes an apparatus and a method with which an improved detection principle for a magnetic field sensor known per se is provided. Due to the improved detection principle, extensive data on the detected objects can be provided, whereby suitable measures regarding the different detected objects can be made.

Preferably, the proposed device may be designed as a system for monitoring a parking area, which can be easily installed due to low cabling and allows a high detection quality of vehicles on the parking area.

Although the invention has been described above by means of concrete examples of application, the person skilled in the art can realize previously or only partially disclosed embodiments, without departing from the gist of the invention.

Claims (13)

Contraption ( 100 ) for detecting an object, comprising: - a magnetic field sensor ( 10 ); A computing device ( 20 ); - a radio-based transmission device ( 30 ); - wherein by means of the magnetic field sensor ( 10 ) and the computing device ( 20 ) a determination of a magnetic field vector in a measuring range of the magnetic field sensor ( 10 ), wherein a change in the determined magnetic field vector can be determined with respect to a defined initial value, wherein data of the detected magnetic field vector is transmitted by means of the transmission device ( 30 ) are transferable; and - an electrical energy store ( 40 ) by means of which the magnetic field sensor ( 10 ), the computing device ( 20 ) and the radio-based transmission device ( 30 ) are supplied with electrical energy. Contraption ( 100 ) according to claim 1, characterized in that a length and an angle of the magnetic field vector can be determined. Contraption ( 100 ) according to claim 1 or 2, characterized in that the initial value of the magnetic field vector in the measuring range of the magnetic field sensor ( 10 ) can be detected without an object. Contraption ( 100 ) according to one of claims 1 to 3, characterized in that in the measuring range of the magnetic field sensor ( 10 ) a geomagnetic field in x-, y-, and z-direction can be determined. Contraption ( 100 ) according to one of claims 1 to 4, characterized in that by means of at least one threshold value (SW1, SW2) for an amount and / or an angle of the magnetic field vector can be determined whether in the measuring range of the magnetic field sensor ( 10 ) an object is located. Contraption ( 100 ) according to claim 5, characterized in that it can be determined whether an angle of the magnetic field vector has changed or whether a length of the magnetic field vector has changed or if the angle and the length of the magnetic field vector have changed, with defined tolerance thresholds for detecting a change are considered. Contraption ( 100 ) according to one of the preceding claims, characterized in that In particular, a vehicle is detectable on a parking area. Contraption ( 100 ) according to any one of the preceding claims, further comprising a second active sensor device, wherein by means of the second sensor device substantially error-free detection of an object in the measuring range of the magnetic field sensor ( 10 ) is feasible. Method for detecting an object by means of a sensor device with a magnetic field sensor ( 10 ), comprising the steps: - determining a magnetic field vector in a measuring range of the magnetic field sensor ( 10 ); Comparing the detected magnetic field vector with a magnetic field vector determined in an initialization phase, and signaling if a change of at least one parameter of the magnetic field vector has been detected. The method of claim 9, wherein an initial value of the magnetic field vector is determined by means of an active sensor device, wherein there is no object in the measuring range of the sensor device. The method of claim 9 or 10, wherein the magnetic field vector is determined in Cartesian coordinates. Method according to one of claims 9 to 11, wherein the signaling of data of the magnetic field vector by means of a radio-based transmission device ( 30 ) is carried out. Computer program product with program code means for carrying out the method according to one of Claims 9 to 12, when it is stored on a computer-readable data carrier or on a computer ( 20 ) expires.

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